This invention is concerned generally with an apparatus and a method for measuring suspended dust particle density and more particularly is concerned with an apparatus and method for reliably generating simulations of actual dust suspension conditions and measuring the associated density of suspended dust.
With the advent of rigorous environmental laws there has been an increased need to accurately predict and to characterize dust suspensions. The concept of measuring dust suspension conditions is generally known in the art. Prior art references show that dust particles can be suspended in air and monitored by dropping or blowing powder materials into a chamber wherein photoelectric sensors measure the magnitude of light intensity transmitted through a path length of suspended dust particles. However, the ability to accurately predict and to characterize dust suspensions in real systems involves the proper generation of the dust suspension. In the prior art there has been little or no effort concerned with generating dust suspension conditions which provide good correlation to results in real systems. Rather, the prior art tends to be simplistic and generates suspensions by simply dropping dust into a tray (see U.S. Pat. No. 2,822,719). Alternatively, the prior art follows a brute force method of installing a photosensor device within an actual operating system having dust suspensions associated therewith (see, U.S. Pat. No. 3,867,640). Such apparatus and methods are insufficient to achieve accurate simulations of any meaningful variety of actual dust suspension conditions and thus do not provide a sound fundamental approach for predicting and characterizing the dustiness present under various real operating conditions.